1. Field of the Invention
This invention relates to coating compositions. More particularly, it relates to solventless, one component, airless sprayable and abrasion resistant polyurethaneacrylate coatings with low curing temperatures.
2. Description of the prior Art
Solvent based resin compositions containing diblocked diisocyanate urea urethane oligomers and coating compositions comprising same are known from U.S. Pat. No. 4,463,143. Additionally, U.S. 4,409,340 teaches a heat curable coating composition consisting essentially of a prepolymer with ketoxime-blocked NCO groups, a diamine crosslinker, optionally an organic solvent and pigments, fillers, blowing agents and other known additives.
U.S. Pat. No. 3,694,389 teaches thermosetting coating compositions which comprise a ketoxime-blocked polyisocyanate and a solution copolymer of an active hydrogen-containing monoethylenically unsaturated compound which is catalyzed by an organo-soluble zinc salt.
U.S. Pat. No. 4,400,497 teaches mixtures comprising a polyisocyanate in the form of discrete particles and a polyol which is useful as coatings and adhesives.
U.S. Pat. No. 4,442,146 teaches a solvent based resin composition comprising a chain-extendable, crosslinkable, diblocked diisocyanate, diurea oligomer, a polyepoxide and an organic solvent.
U.S. Pat. No. 4,456,740 teaches a resin composition comprising chain-extendable, crosslinking polyol having at least three hydroxyl groups, a chain-extendable, diblocked diisocyanate, diurethane oligomer reaction product of a diol with a half-blocked diisocyanate and a crosslinking agent reactive with the hydroxyl functionality of said polyol and substantially unreactive with the de-blocked isocyanate functionality of said diblocked diisocyanate diurethane oligomer.
U.S. Pat. No. 4,456,739 teaches a resin composition comprising a chain-extendable, crosslinkable polyol being the reaction product of a diepoxide with a diol, said polyol having at least three hydroxyl groups, a chain-extendable, diblocked diisocyanate diurea oligomer and a crosslinking agent reactive with the hydroxyl functionality of said polyol and substantially unreactive with the de-blocked isocyanate functionality of said diblocked, diisocyanate diurea oligomer.
U.S. Pat.No. 4,248,756 teaches a thermosetting, two-component coating composition containing a ketoxime-blocked aromatic isocyanate and specific amine crosslinking agents.
U.S. Pat. No. 3,857,818 teaches a powder coating composition comprising a mixture of ketoxime-blocked isocyanate prepolymer and a hydroxy-functional resin.
The aforesaid prior art has various disadvantages. For example, the solvent containing materials present toxicity and in some cases flammability hazards along with pollution problems. Government regulations are now requiring lowering of the volatile organic content ("VOC") in various industries including the automotive industry which uses said coatings as underbody coatings. Additionally, some of the above prior art compositions have too elevated a curing temperature to be operable in present day commercial ovens which provide temperatures in the range 100.degree.-150.degree. C.
One object of the instant invention is to provide a one component, storage stable, heat curable, solventless, coating composition. Another object of the instant invention is to provide an airless sprayable coating composition. A further object of the invention is to provide a coating composition with a curing temperature in the range 80.degree.-120.degree.0 C. Still another object of the invention is to provide a coating which is abrasive resistant and has good adhesion to metal substrates. A still further object of the instant invention is to provide a coating which provides good corrosion protection. Other objects will become apparent from a reading hereinafter.